Refrigeration apparatus



May 25, E E GRQVER REFRIGERATION APPARATUS Filed Dec. 5, 1933 LEVEL FRIGERRNT WITNESSES: INVENTOR 7(4 [1 ELLIOTT E.GROVER I BY ATTOEY Patented May 25, 1937 lTED STATES REFRIGERATION APPARATUS Elliott E. Grover, Springfield, Mass, assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa, a corporation of Pennsylvania Application December 5, 1933, Serial No. 701,028

6 Claims.

- the domestic type.

More particularly, my invention relates to a cooling unit of the flooded type, wherein vaporized refrigerant is withdrawn separately from a plurality of independent vapor spaces in the cooling unit and is returned to a pressure translating device of a refrigerating system, preferably through a single suction conduit.

Heretofore, in evaporators or cooling units of the above type, vaporized refrigerant has been withdrawn directly from the independent vapor spaces, or headers, of the evaporator by means of interposed conduit connections disposed exteriorly of the headers and of the refrigerant containing duct connections between the headers, so that substantially equal pressures will prevail in the headers to insure uniform vaporization from all parts of the evaporator. A single suction conduit is usually provided to connect the interposed conduit connections between headers, for returning vaporized refrigerant to the high side of the refrigerating system.

Such a construction requires a welded or brazed connection at the joint where the connecting conduits enter each independent vapor space and at least one other welded or brazed connection for the suction conduit joint. The joining operations not only add expense to the evaporator, but also add to the difiiculty of porcelainizing, and cause many rejections in this process. Furthermore, the exteriorly disposed conduits connecting the vapor spaces take up valuable space either in the food compartment, or

in the freezing chamber usually formed by the evaporator of domestic refrigeration apparatus.

It is an object of my invention, therefore, to insure substantially equal pressures in the vapor spaces of an evaporator of the type described by means entirely disposed within the confines of the evaporator proper.

It is another object of my invention to reduce the number of pipe joining operations necessary in manufacturing evaporators of the type having a plurality of refrigerant vapor spaces from .whence refrigerant vapor is withdrawn.

It is a further object of my invention to provide for the maximum usable space in a domestic refrigerator cabinet having an evaporator therein provided with a plurality of vapor spaces from whence refrigerant vapor is withdrawn.

It is still another object of my invention to provide for the introduction, circulation and removal of refrigerant and lubricant in an evaporator of the type described, to obtain highly efiicient operation.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

Fig. 1 is a front view, partly in section, of a complete refrigerating system and parts of a refrigerator cabinet, and, illustrates an embodiment of my invention; and,

Fig. 2 is a side elevational view of the coolin unit shown in Fig. 1,

In general, I have shown my invention applied to a double-header welded evaporator wherein the two upper or main headers are connected together by means of a conduit disposed in one of the corrugations of the evaporator, which corrugations extend between the headers to form a freezing chamber and communicate at their opposite open ends with respective headers. One end of the conduit is connected to the suction side of a compressor, the other end of the conduit opening directly into one of the headers for removal of vaporized working fluid therefrom. An aperture is formed in the conduit above the level of the liquid working fiuid in the other header, 'for the removal of vaporized working fluid from said header. The aperture is of such a size that a slight difference in pressure prevails between the headers when the pressure translating device of the refrigerating system is operating to insure flow of working fluid from both headers to the pressure translating device of the refrigerating system.

It is obvious to those skilled in the art that means contained in the confines of the evaporator other than an inserted suction conduit may be devised for removing vapor, that other than welded evaporators may be used and that various refrigerants and lubricants may be chosen without departing from the spirit of my invention, and, therefore, I do not wish to be limited to these specific details except as set forth in the appended claims.

Referring specifically to the drawing for a detailed description of my invention, I have shown in Fig. 1 a conventional compression refrigerating system in a refrigerator cabinet I. Refrigerant is compressed by a pressure translating device or compressor 3 driven by a motor 4, both the motor and compressor being contained in a sealed casing 2. Compressed refrigerant vapor is conveyed to a condenser 5 where it is cooled 6. The liquid refrigerant is then conveyed to a high side float valve 1, and when suificient liquid has accumulated therein, the float valve allows liquid refrigerant to enter the evaporator or cooling unit 8, as is well understood in the art. The casing 2, condenser 5, fan 6 and float valve 7 are contained in machine compartment 9. The suction ,pressure of the. compressor prevails in the evaporator and, refrigerant liquid is, therefore, vaporized and extracts heat from the food storage compartment ll in cabinet wherein the evaporator 8 is disposed. Vaporized refrigerant isthen returned to compressor 3 through conduit in, whereupon the cycle is repeated. The motor operates the compressor intermittently in response to evaporator temperature by means of a temperature control mechanism diagrammatically illustrated and essentially comprising a bulb l2 on the evaporator 83 which contains an elastic medium such as S02, changes in pressure in which are translated to a bellows iii to open and close switch means l4.

The condenser, high pressure side of the compressor and float valve may be designated as a high refrigerant pressure zone while the evaporator is designated as a low refrigerant pressure zone. In the embodiment shown, the sealed casing 2 is also in the low pressure zone. I have shown a refrigerant and lubricant which are substantially immiscible, the lubricant being of a lower specific gravity than the refrigerant. An example of such a combination is S02 and ordinary mineral lubricant, such as that sold under the trade name of Nujol. With such a working fluid, refrigerant and lubricant are circulated through the entire system together and stratify in the evaporator as shown at Hi. The lubricant, however, must be removed from the evaporator and returned to other parts of the system to insure proper lubrication thereof The refrigerant and lubricant mentioned above are given only by way of example.

Referring now to the drawing, Figs. 1 and 2, I have shown a U-shaped welded evaporator comprising nested sheet metal members I! bent to form a freezing chamber l5. Corrugations I8 are formed in the outer nested member and headers |9 and 20 are formed at the top of the U. The nested members are welded at their unconnected edges at |8a and between the corrugations at lBb to form rigid closed chambers |8c opening at opposite ends into the respective headers 20 and 2|. The chambers |8c are filled with liquid working fluid to the level shown. Vapor spaces 22 and 23 are, therefore, present in headers 20 and 2|, respectively, above the liquid working fluid level. Liquid working fluid is conveyed to the evaporator through a conduit 24 which extends into one of the corrugations l8 and is then conveyed to a lower auxiliary header 25, from whence it circulates upwardly through corrugations toward the vapor spaces 22 and 23. This method for conveying liquid working fluid to a flooded evaporator is fully set forth in Patent No. 1,928,467, F. L. Tarleton for Refrigerating apparatus, and assigned to the assignee of the present application.

As working fluid collects in the evaporator, and refrigerant'and lubricant stratify, refrigerant liquid vaporizes into spaces 22 and 23, and is conveyed back to the compressor by the suction thereof. The suction pressure on each of v the headers 20 and 2| should be substantially the same to insure uniform evaporation from all parts of the evaporator 8. In order to obtain equal pressure in the headers, I provide a conduit 26, one end of which connects with suction conduit ill. The conduit 26 extends through header 20 and completely around the U-shaped evaporator. The other end of conduit 26 opens at 26 into vapor space 23 in header 2| to ,withdraw refrigerant vapor therefrom. An aperture 2'8 is provided in the conduit in the vapor space 22 in header 20 for withdrawing refrigerant vapor therefrom. The aperture 2? is of such size with respect to opening 28 and the length of the conduit 26, that a slightly lower pressure prevails in the conduit 26 at the aperture 211, than in header 2|, thus ensuring flow of vapor from header 2| to suction conduit l0 when the compressor operates. Vapor is, therefore, withdrawn from the independent vapor spaces 22 and 23 and returned to the compressor by means substantially within the confines of the headers 20 and 2| and corrugations l1.

Bafile plates 29 and 30 are disposed in headers 20 and 2| adjacent conduit 26 at a small dis-' tance above the normal refrigerant level in each header, to prevent liquid refrigerant from boiling up and entering the conduit 26, thereby preventing liquid refrigerant from being conveyed to the compressor 3 without accomplishing any appreciable refrigerating effect in the evaporator.

The baflle plates therefore improve the efiiciency of the refrigerating system.

The opening28 and aperture 21 are so positioned in relation to the lubricant level in, the evaporator that, when the level rises in one or both of the headers 20, 2|, lubricant enters aperture 21 and opening 28, is entrained by the refrigerant vapor therein, and returned to the compressor 3.

From the foregoing, it will be apparent that I have provided an evaporator having a plurality of independent refrigerant vapor spaces therein in which introduction, circulation, and removal of refrigerant are accomplished in a manner to obtain maximum efliciency; furthermore, the evaporator is constructed with the minimum amount of welding and space in the freezing chamber and food compartment is conserved. I have also provided for lubricant return to the pressure translating device from the evaporator and for prevention of liquid refrigerant return to the compressor from the evaporator.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically setforthin the appended claims.

What I claim is:

'1. An evaporator including an enclosed chamber for liquid refrigerant, and having a plurality of independent refrigerant vapor spaces connected with the liquid chamber for containing refrigerant vapor and means for connecting the refrigerant vapor spaces above the level of the liquid, said means being substantially contained within the confines of the chamber-and the refrigerant vapor' spaces.

2. An evaporator comprising nested sheet metal .members; a plurality of corrugations formed in one of the members, welded connections for the nested members at the unconnected edges thereof and between the corrugations, liquid refrigerant working fluid in the corrugations, said members 4 ing chambers formed by the corrugations, said members being so connected and bent as to provide a plurality of independent refrigerant vapor spaces above the liquid refrigerant containing chambers, and means for connecting the vapor spaces, said means being substantially contained within the confines of the corrugations and the vapor spaces.

3. An evaporator including a plurality of head-,- ers partially filled with a liquid working fluid, a plurality of ducts forming 'a freezing compartment, said ducts being filled with the working fluid and connecting with the headers, and means for connecting the spaces above the liquid working fluid in the headers, said means being substantiallycontained Within the confines of said headers and ducts. 7

4. An evaporator including a plurality of headers, a plurality of ducts connecting with the headers and forming a freezing compartment, said ducts being filled with a liquid working fluid, and means for connecting the headers together to withdraw vaporous working fluid therefrom, said means being substantially contained within the confines of said headers and ducts.

5. An evaporator construction embodying sheets of metal formed to provide a freezing chamber and comprising spaced planular side walls and a connecting bottom wall, said-sheets of metal cooperating to form a refrigerant-containing passageway and a pair of headers connecting with said passageway at the upper ends of both of said side walls, said headers having refrigerant vapor spaces therein for collecting refrigerant vapor from said passages, and a connecting conduit between said vapor spaces having a configuration substantially conforming with the side and bottom walls of said freezing chamber and disposed adjacent thereto.

6. An evaporator comprising inner and outer sheet metal shells formed to provide vertical side walls and a connecting bottom wall, said shells having portions spaced from each other to provide a refrigerant containing chamber, a header disposed near the upper end of each of the side walls for containing refrigerant liquid and vapor, and a cross header connecting said headers, said cross header being located between the shells and extending vertically in the side walls and horizontally in the bottom wall.

ELLIOTT E. GROVER. 

